Alfonso V, King of Portugal, the Algarves and of either side of the sea in Africa, Lord of Ceuta and Alcácer in Africa (Sintra, 15 January 1432 - Lisbon, 28 August 1481), married 1stly in ? on 6 May 1447 Princess Isabel of Coimbra (Portugal) (Evora, 1 March 1432 - ?, 2 December 1455); married 2ndly in Plasencia on 30 May 1475, Princess Juana 'La Beltraneja' of Castille (Madrid, 28 February 1462 - Coimbra or Lisbon, ? 1530)

Reign: 1448 -1477 and 1477 - 1481, from 1438 to 1448 under the regency of his mother Queen Leonor and later under the regency of his uncle Prince Pedro, Duke of Coimbra, and from 1477 to 1481 under the regency of his son Prince João, later King João II of Portugal

Afonso V (pronounced [ɐˈfõsu] in Portuguese; English Alphonzo), or Affonso (Archaic Portuguese), the African (Port. o Africano) (on January 15, 1432 – August 28, 1481), was the 12th king of Portugal and the Algarves.He was born in Sintra, the eldest son of King Edward of Portugal by his wife, Infanta Eleanor of Aragon. Afonso V was only six years old when he succeeded his father in 1438.During his minority, Afonso V was placed under the regency of his mother, according to a late will of his father. As both a foreigner and a woman, the queen was not a popular choice for regent. Opposition rose and the queen's only ally was Afonso, Count of Barcelos, the illegitimate half brother of Duarte I and count of Barcelos. In the following year, the Cortes (assembly of the kingdom) decided to replace the queen with Infante Pedro, Duke of Coimbra, the young king's oldest uncle. His main policies were concerned with avoiding the development of great noble houses, kingdoms inside the kingdom, and concentrating power in the person of the king. The country prospered under his rule, but not peacefully, as his laws interfered with the ambition of powerful nobles. The count of Barcelos, a personal enemy of the Duke of Coimbra (despite being half-brothers) eventually became the king's favourite uncle and began a constant struggle for power. In 1442, the king made Afonso the first Duke of Braganza. With this title and its lands, he became the most powerful man in Portugal and one of the richest men in Europe . To secure his position as regent, in 1445 Pedro married his daughter, Isabel of Coimbra, Infanta of Portugal, to Afonso V.But in June 9, 1448, when the king came of age, Pedro had to surrender his power to Afonso V. The years of conspiracy by the Duke of Braganza finally came to a head. In September 15 of the same year, Afonso V nullified all the laws and edicts approved under the regency. The situation became unstable and, in the following year, being led by what he afterwards discovered to be false representations, Afonso declared Pedro a rebel and defeated his army in the Battle of Alfarrobeira, in which both his uncle and father in law was killed. After this battle and the loss of one of Portugal's most remarkable infantes, the Duke of Braganza became the de facto ruler of the country.

Infanta Isabel of Coimbra (Isabella of Portugal) (1 March 1432 – December 2, 1455) was a Portuguese infanta and the first wife of King Afonso V of Portugal.She was a daughter of Infante Pedro, Duke of Coimbra and Isabel of Aragon. Her maternal grandfather was Jaume II, Count of Urgell.Isabel and Afonso V were married on May 6, 1448. Both the bride and groom were sixteen. They had three children:

Juana of Castile, known also as the Beltraneja (1462 – 1530) was a princess of Castile.Her birth caused a scandal in the Castilian court. Her mother was Joana, princess of Portugal, the consort queen of king Henry IV of Castile. The king had no other children from this or the previous marriages and rumour said he was impotent. Because of this and the fact that Joana of Portugal was having a notorious affair with Beltrán de La Cueva, a Castilian noble, Juana was never considered legitimate. Moreover, she was nicknamed the Beltraneja (a mocking reference to her assumed real father) from the cradle. Her mother was banished to Bishop Fonseca's castle where she fell in love with Fonseca's nephew and became pregnant. Henry divorced her.Legitimate or not, Joanna remained the only child that could be remotely attributed to Henry IV of Castile. He even made the nobles of Castile swear alliance to her and promise that they would support her as queen. After a few unsettled arrangements, that included French and Burgundian princes, Joanna was promised in marriage to her uncle, King Afonso V of Portugal, who swore to defend her (and his own) rights to the crown of Castile. But when Henry died in 1474, nobody took Juana's cause seriously and the crown went to Isabella I of Castile, her aunt, initiating a four-year War of the Castilian Succession.

According to Wikipedia, she was appointed regent in accordance with his father's wishes. However, she was unpopular owing to the fact that she was foreign and female, and didn't have any allies among the nobility other than her husband's illegitimate half brother.